Conventional X-ray diagnostic apparatuses include a grid on the detection face side of an X-ray detector in order to remove scattered X-rays (scattered radiation) occurring in a subject. The grid, for example, has lead foils that absorb X-rays and intermediate substances (aluminum or fiber, for example) that absorb less X-rays alternately and causes the lead foils to absorb the scattered radiation to remove the scattered radiation. The grid has the lead foils and the intermediate substances so as to give a certain lattice density (the number of lead foils per unit length).
When a flat panel detector (FPD) is used as the X-ray detector in the X-ray diagnostic apparatus, interference fringes caused by pixels of the FPD and a lattice of the grid may occur in X-ray images. Such interference fringes as artifacts deteriorate the performance of diagnosing X-ray images. In view of this, some methods are known as methods for inhibiting the occurrence of such interference fringes. Examples thereof include matching the lattice density of the grid with the pixel pitch of the FPD and using a grid having a lattice density high enough not to be able to convert input signals even by the FPD. However, there may be cases where the above conventional techniques have difficulty in reducing radiation exposure while maintaining image quality.